Dryer

ABSTRACT

A DRYER FOR LAUNDRIES AND THE LIKE HAVING A DRUM ROTATABLE ABOUT AN AXIS IN A STATIONARY CASING. DRYING AIR IS SUPPLIED THROUGH AN ENCLOSURE AT THE CENTRAL PORTION OF THE REAR WALL AND IS BLOWN BY A FAN. THE DRUM IS PROVIDED WITH A PLURALITY OF APERTURES IN THE FRONT WALL TO DISCHARGE THE DRYING AIR. THE CASING IS CONSTRUCTED IN SUCH A WAY THAT THE DRYING AIR IS RETURNED FROM THE FRONT TO THE REAR OF THE DRUM WHERE PART OF THE AIR IS FED TO THE ENCLOSURE CONTAINING THE FAN THROUGH A NARROW OPENING AT THE REAR END OF THE ENCLOSURE AND THE REST OF THE AIR IS EXHAUSTED INTO THE ATMOSPHERE.

United States Patent US. Cl. 34-133 3 Claims ABSTRACT OF THE DISCLOSUREA dryer for laundries and the like having a drum rotatable about an axisin a stationary casing. Drying air is supplied through an enclosure atthe central portion of the rear wall and is blown by a fan. The drum isprovided with a plurality of apertures in the front wall to dischargethe drying air. The casing is constructed in such a way that the dryingair is returned from the front to the rear of the drum where part of theair is fed to the enclosure containing the fan through a narrow openingat the rear end of the enclosure and the rest of the air is exhaustedinto the atmosphere.

The invention relates to a dryer and more particularly to a dryer forlaundry, suitable for use in the home and of the type with a drumrotatable about an axis in a stationary casing, in which the drying airis supplied through an enclosure of the fan through the central portionof the rear wall and the drum is provided with apertures to dischargethe drying air.

Such a dryer is known from the Dutch Pat. 109,682. In this known dryerthe drying air is discharged right away through the discharge aperturesto the atmosphere and so that only dry heated fresh air is blown intothe drum.

The general object of the invention is to provide a novel dryer of thetype mentioned in the first paragraph having a better efiiciency thanthe dryer known from said Dutch patent. To this end the dryer of theinvention is characterised in that the casing is constructed in such away that the drying air is brought back from said discharge openingsinto the enclosure of the fan through a narrowed opening at the rear endof the enclosure debouching into a wide duct communicating with theatmosphere, and that a discharge opening to the atmosphere is providedin the path along which the air is brought back through the casing.

By means of these measures only a part of the air passing through thedrum is discharged and fresh air is only supplied to replace thedischarged air. The amount of discharged air might be enlarged orreduced at a constant diameter of the discharge opening by reducing orenlarging the narrowed opening, it being possible in this way to have anoptimum efliciency at a determined heating capacity. From tests itappeared that with the dryer according to the invention a substantialimprovement of the efficiency can be reached.

Also according to the invention the narrowed opening is an annular slitbetween the rear end of the enclosure of the fan and a wall of thecasing, said wall leaving an opening substantially corresponding to theinlet opening for the drying air of the enclosure.

In this way a simple device is obtained with a great cross-section areafor the supply of fresh air.

With a dryer having a drum with its axis horizontal and the front wallof the drum being provided with a closable opening to insert or withdrawthe laundry, and with the rear wall of the drum being tapered towardsthe front wall, according to the invention preferably the dischargeopenings are only provided in the portion of the front wall beside theclosable opening, the casing being provided with walls forming togetherwith said portion of the front wall of the drum, the cylindrical part ofthe drum and said rear wall of the drum the path to bring back thedrying air.

In this embodiment the drying air is completely passed round thelaundry, said rear wall having not only the known advantage of leadingthe laundry along the opening through which the drying air is blown intothe drum, but also the advantage of a greater space for the circulatingair before entering the narrowed opening, in this way no throttling cantake place in said space.

Other objects and advantages will become apparent from the followingdescription taken in connection with the accompanying drawings.

A drum 1 of the dryer rotatable about its horizontal axis has in itsfront wall 2 a filling opening 3, the rear wall 4 being formed as afrustum of a cone.

In the space formed by the conical rear wall 4 of the drum is provided apressure fan 5 with an enclosure 6, said fan 5 bearing in said rear wall4 and air being blown with a certain overpressure through said enclosureinto the drum 1.

The air is discharged from the drum 1 through apertures 7 in the frontwall 2 aside the filling opening 3 and is then passed through the spacesbetween the portion of the front wall 2 of the drum 1 provided withapertures 7 and the wall 8 of the stationary casing, between thecylindrical wall 9 of the drum 1 and the wall 10 of the casing, andbetween the rear wall 4 of the drum and the wall 11 of the casing to anannular slit 12 between the rear end of the enclosure 6 and the inneredge 13 of the wall 11 of the casing. From there the air passes againthrough the enclosure 6 into the drying space.

In the wall 11 of the casing there is provided an opening 14communicating the space between the rear wall 4 of the drum 1 and thewall 11 of the casing with the atmosphere, through which a portion ofthe drying air is driven to the atmosphere.

The opening formed by the inner edge 13 in the wall 11 communicates withthe atmosphere. Near said opening is provided an electrical heatingdevice 16 serving to heat the fresh air drawn in by means of the flow ofthe air passing through the slit 12.

The path of the air passing through the device is indicated with arrows.

It appeared from tests that with the same consumption of energy thedevice according to the invention evaporates about 25% more water than adevice according to the Dutch Pat. 109,682. In said tests thetemperature of the atmosphere was 18-20 C. at a relative humidity of theair of 50 to 60%. It appeared that the best results were obtained withan overpressure of the fan of about 8 millimeters, a relative humidityof the discharged air of about and a discharged amount of 6- 4 of thetotal amount of air circulating through the device.

It is noted that the invention is not restricted to the shown anddescribed embodiment. It is e.g. also possible to provide a device witha drum having its axis vertical with a recirculation system of thedrying air. It is also possible to obtain the function as an injector bypassing said air through an annular space with an axis coaxial with thedriving shaft.

The embodiment according to the drawings, however, is preferred becauseof the already known advantage of the rear wall of the dryer with itsshape of a frustum of a cone and because of the advantage that the slitcan be provided in a more simple way than the annular space.

What I claim is:

1. A dryer for laundries and the like comprising a stationary casing, adrum rotatably mounted within said casing and forming an annular spacetherebetween, means to rotate said drum, a fan enclosure substantiallycentrally mounted in one end of said drum, an air inlet opening in saidcasing adjacent said enclosure, one end of said enclosure being open toatmosphere through said opening, a fan mounted in said enclosure,apertures formed at the end of said drum remote from said enclosure,said fan drawing air in through said enclosure from the atmosphere andpassing it through said drum and said apertures to return via saidannular space formed between said casing and said drum, and passagemeans for ejecting part of said return air to atmosphere and feeding theremainder to said enclosure wherein it is mixed with ambient air andrecirculated through said dryer.

2. A dryer according to claim 1 wherein said passage means comprises aradial slit formed between the open end of the fan enclosure and a Wallof said casing, said inlet opening in said casing being of substantiallythe same size as said open end of the enclosure and slightly spaced 4therefrom, said slit providing a ath for the recirculating air.

3. A dryer according to claim 1 in which said drum has a horizontal axisand is provided with front and rear end walls, a filling opening in saidfront wall, means to close said filling opening, said apertures beingprovided in that portion of the front end wall adjacent the fillingopening, said rear end wall having a frusto-conical shape directedtowards said front end wall, said enclosure being mounted in said rearend wall.

References Cited UNITED STATES PATENTS 3,060,593 10/1962 Flora et a1.34-133 3,333,346 8/1967 Brucken 34-l33X 3,402,477 9/1968 Hubbard 34-133X3,419,969 1/1969 Freze 34-133X 2,996,809 8/1961 Shahter 34133 3,483,63212/1969 Triplett 34--133X MARTIN P. SCHWADRON, Primary Examiner T. W.STREULE, Assistant Examiner

